A community-wide promotion of asthma self-management in New Zealand.

Asthma affects approximately 9% of young adults in New Zealand, with evidence of an increase in prevalence over recent years. Morbidity and mortality from this condition have caused widespread concern. In response to identified deficiencies in asthma management, initiatives to promote self-management using an asthma action plan were promoted throughout the Canterbury region in 1991 as part of a regional pilot study. A resource kit was prepared and self-management principles were promoted to general practitioners in discussion workshops. A community-wide promotion of the action plan was followed by a process and outcome evaluation. The plan and associated resources were well received by doctors and patients. Seventy-seven percent of doctors responding to a questionnaire had used the plan, and of these, 94% indicated that they would continue to use the plan in the future. Patients who obtained a completed plan experienced a greater reduction in nocturnal waking with asthma and improved self-management skills.

A microcomputer-based interactive cough sound analysis system.

The occurrence and nature of cough sounds, especially those occurring in asthma in young children, is of considerable interest to workers in paediatrics and general practice. To facilitate our research into the characteristics of such sounds, we have developed a microcomputer-based analysis system, which we call COFF. In this paper we discuss the design and implementation of the system, emphasising its user-friendly, interactive features, and the manner in which it efficiently manages the large amounts of data that research into sounds incurs. We illustrate the operation of the system with examples of spectrograms computed from cough sounds recorded simultaneously at the mouth and through the chest wall.

General practitioner fees: the effect of an additional 10% goods and services tax.

The effects of an increase in general practitioner fees on the timing of decisions to seek certain consultations were studied at the time of the introduction of a 10% goods and services tax (GST) on 1 October 1986. Fifty-six general practitioners collected information on 4113 consecutive paediatric consultations over a four week study period. The price rise itself appeared to have little or no effect either on numbers attending, pattern of illness or on the timing of consultations. However, private medical insurance may have influenced decisions on when to seek medical attention.

Active approach to recognising asthma in general practice.

The general practice medical records of 214 children born in 1977 were scrutinised for a diagnosis of asthma. In 18 (8%) of these a diagnosis of asthma had been entered. Using a scoring system based on the medical record a further group of children who were thought likely to have undiagnosed asthma was exercise tested. Twelve children (6%) had demonstrable exercise induced asthma. In addition, seven children (3%) had both frequent respiratory symptoms and borderline exercise test results, indicating that they too had clinically important airways obstruction. As expected, histories of atopic eczema, nocturnal cough, persistent cough (more than one week), and wheezing appeared often in the medical records of the children with asthma. In combinations these diagnostic clues were more than 50% predictive of asthma. A more active approach in general practice to the diagnosis of asthma in children is both necessary and possible.

Towards a quantitative description of asthmatic cough sounds.

This study describes a method of quantitatively characterizing cough sounds using digital signal processing techniques. Differences between asthmatic and non-asthmatic cough sounds are presented. Coughs from 12 asthmatic and 5 non-asthmatic subjects were analysed. Cough sounds and flows were digitized, at a sampling rate of 5 kHz, before and after a free-running exercise test. Individual coughs were divided into two or three phases, corresponding to the initial glottal opening burst, the quieter middle phase, and (sometimes) the final closing burst. Standard signal processing techniques were then invoked to characterize the spectral and temporal shapes of the first two phases. Factor analysis indicated that the spectral shapes of the two phases are independent, with each being largely described by the degree of "peakedness" in the spectrum, and by the balance of energy between low and high frequencies. Both the duration of the initial burst and zero-crossing rates of the cough waveform (which indicates the "spectral balance") during each of the first two phases were smaller for asthmatic than for non-asthmatic coughs. Fewer asthmatic coughs contained a final burst. Discriminant analysis between the two groups gave classification error rates of 20-30%. The peak flow recorded during the cough was significantly smaller for asthmatics, and correlated very well with the peak flow recorded during forced expiration. Thus, significant differences exist between asthmatic and non-asthmatic cough sounds. An effective representation of the temporal structure of the cough sound is required to successfully characterize the cough.

A portable system for the spectral analysis of cough sounds in asthma.

A practical and portable method is described to analyze the sound spectra of coughs. The system is based upon a personal computer and simultaneously collects the sounds of cough heard both at the mouth and through the chest wall together with the airflow at the mouth produced during the cough. Subsequent analysis produce spectrographs of the cough sound linked to the corresponding airflow. The system will be used initially to examine the effects of exercise on the sound of cough in asthma. Further study of cough spectra in this way may be useful in the management of asthma either diagnostically or in the assessment of therapeutic interventions.

Night cough and general practice research.

Thirty-four children, aged between three and nine years, presenting with nocturnal cough, were studied on successive nights using an automatic voice activated tape recorder system. Children with a family history of atopy coughed significantly more than children without such a family history. A wide variation in cough frequency was found both between and within subjects. No effects of treatment on cough frequency were demonstrated. Some of the physiological and pathological mechanisms underlying night cough are discussed.

Cough sound analysis: a new tool for the diagnosis of asthma?

A method of computerized cough sound analysis is described. The sounds of nocturnal and post-exercise coughs from a child with asthma were compared with those from a child without asthma. The spectrographic patterns of voluntary cough at rest from the two children were similar. The pattern seen after exercise from the asthmatic child was different from the resting cough but similar to that seen during recorded nocturnal cough. In contrast the post-exercise cough from the non-asthmatic child was similar to the cough seen at rest. Refinement of this method of cough sound analysis may be useful in the diagnosis of asthma in young children.

Evaluation of a self-management plan for chronic obstructive pulmonary disease.

We hypothesized that the use of an Action Plan might assist self-management for patients with chronic obstructive pulmonary disease (COPD). A pilot process and randomized, controlled study were undertaken to evaluate an Action Plan that provided advice on management of usual care and exacerbations, together with a booklet on self-management. Fifty six subjects with COPD recruited through general practitioners (GPs) completed the 6 month study, 27 in the control group and 29 in the intervention group. The control group received usual care from their GP, and the intervention group received a booklet and Action Plan from their practice nurse plus a supply of prednisone and antibiotic from their GP. The two groups were demographically similar with a mean age of 68 yrs. The resources were well received by GPs, practice nurses and intervention group subjects. After 6 months, there were no differences in quality of life scores or pulmonary function. There were significant changes in self-management behaviour in the intervention group compared to controls. In response to deteriorating symptoms, 34 versus 7% (p=0.014) initiated prednisone treatment and 44 versus 7% (p=0.002) initiated antibiotics. Subjects in the intervention group readily adopted self-management skills but did not show any difference in quality of life or lung function parameters. A larger, prospective, controlled, clinical trial of this approach is warranted.

Respiratory effects of air pollution in chronic obstructive pulmonary disease: a three month prospective study.

BACKGROUND: A study was undertaken to investigate the relationship between air pollution levels and respiratory symptoms and peak expiratory flow rate (PEFR) in subjects with chronic obstructive pulmonary disease (COPD) living in Christchurch, New Zealand. METHODS: Forty subjects aged over 55 years with COPD completed twice daily diaries for three months during the winter of 1994. Subjects recorded respiratory symptoms, PEFR, outdoor activity, visits to doctor or hospital, and medication use. All were resident within a 5 km radius of the regional council's air pollution monitoring site. Daily and hourly mean pollutant levels (particulates (PM10, nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO)) were measured at the monitoring site. RESULTS: Pollution levels were generally low relative to those recorded in previous years. The New Zealand Ministry for the Environment guidelines for PM10 were exceeded on five occasions, and for CO six times. No association was found between PEFR and any of the pollution variables. A rise in the PM10 concentration equivalent to the interquartile range was associated with an increase in night time chest symptoms (relative risk 1.38, 95% CI 1.07 to 1.78). A rise in NO2 concentrations equivalent to the interquartile range was associated with increased reliever inhaler use (relative risk 1.42, 95% CI 1.13 to 1.79) and for 24 hour lag analysis with increased nebuliser use (relative risk 2.81, 95% CI 1.81 to 4.39). There was no increase in the relative risk of other symptoms in relation to pollution levels. CONCLUSIONS: These effects, demonstrated in a small susceptible group of subjects with COPD, indicate that adverse outcomes can be measured in response to pollution levels that are within current guidelines.